openssl/crypto/idea/i_cbc.c

/*
 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <openssl/idea.h>
#include "idea_lcl.h"

void IDEA_cbc_encrypt(const unsigned char *in, unsigned char *out,
                      long length, IDEA_KEY_SCHEDULE *ks, unsigned char *iv,
                      int encrypt)
{
    register unsigned long tin0, tin1;
    register unsigned long tout0, tout1, xor0, xor1;
    register long l = length;
    unsigned long tin[2];

    if (encrypt) {
        n2l(iv, tout0);
        n2l(iv, tout1);
        iv -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            n2l(in, tin0);
            n2l(in, tin1);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            IDEA_encrypt(tin, ks);
            tout0 = tin[0];
            l2n(tout0, out);
            tout1 = tin[1];
            l2n(tout1, out);
        }
        if (l != -8) {
            n2ln(in, tin0, tin1, l + 8);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            IDEA_encrypt(tin, ks);
            tout0 = tin[0];
            l2n(tout0, out);
            tout1 = tin[1];
            l2n(tout1, out);
        }
        l2n(tout0, iv);
        l2n(tout1, iv);
    } else {
        n2l(iv, xor0);
        n2l(iv, xor1);
        iv -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            n2l(in, tin0);
            tin[0] = tin0;
            n2l(in, tin1);
            tin[1] = tin1;
            IDEA_encrypt(tin, ks);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2n(tout0, out);
            l2n(tout1, out);
            xor0 = tin0;
            xor1 = tin1;
        }
        if (l != -8) {
            n2l(in, tin0);
            tin[0] = tin0;
            n2l(in, tin1);
            tin[1] = tin1;
            IDEA_encrypt(tin, ks);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2nn(tout0, tout1, out, l + 8);
            xor0 = tin0;
            xor1 = tin1;
        }
        l2n(xor0, iv);
        l2n(xor1, iv);
    }
    tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
    tin[0] = tin[1] = 0;
}

void IDEA_encrypt(unsigned long *d, IDEA_KEY_SCHEDULE *key)
{
    register IDEA_INT *p;
    register unsigned long x1, x2, x3, x4, t0, t1, ul;

    x2 = d[0];
    x1 = (x2 >> 16);
    x4 = d[1];
    x3 = (x4 >> 16);

    p = &(key->data[0][0]);

    E_IDEA(0);
    E_IDEA(1);
    E_IDEA(2);
    E_IDEA(3);
    E_IDEA(4);
    E_IDEA(5);
    E_IDEA(6);
    E_IDEA(7);

    x1 &= 0xffff;
    idea_mul(x1, x1, *p, ul);
    p++;

    t0 = x3 + *(p++);
    t1 = x2 + *(p++);

    x4 &= 0xffff;
    idea_mul(x4, x4, *p, ul);

    d[0] = (t0 & 0xffff) | ((x1 & 0xffff) << 16);
    d[1] = (x4 & 0xffff) | ((t1 & 0xffff) << 16);
}